Regardless of climatic conditions, commercial, institutional and industrial buildings are air conditioned due to the steady escalation of internal heat gains. Depending on the type, building occupancy and climate, the cost of air conditioning systems vary from 10 to 30 percent of total construction costs with the cooling plant accounting for more than half of the total air conditioning system cost.
In the various industrial sectors many process and manufacturing operations involve process cooling to maintain the plant performance, with the required cooling system representing a significant portion of the overall plant capital, amortization and operating costs.
Combinations of unit operations used in cooling systems may include heat exchange, indirect and direct evaporative cooling, mechanical vapour compression refrigeration, absorption refrigeration and adsorption or absorption dehumidification. Alternative combinations of these operations are being sought by users seeking lower operating costs and by utilities facing increasing demand for electric power used to operate these facilities.
One prior art system recently developed by Cargo Caire Engineering Corp. (Gas Research Institute Digest, Vol. 8. No. 4., Winter 1985/86, p. 30) uses a combination of adsorption dehumidification, vapour compression refrigeration, evaporation and heat exchange operations to dehumidify and cool the outdoor air for use in air conditioning of space. In the adsorption dehumidification stage of the treatment the prior art system uses a rotating adsorbent wheel concept with a waste heat recovery heat exchanger to improve the efficiency of the adsorption stage and uses natural gas as fuel to preheat the air used to reactivate spent adsorbent.
Another prior art system described by U.S. Pat. No. 4,222,244 issued to G. Meckler, uses a combination of adsorption rotating wheel dehumidification, vapour compression refrigeration and heat exchange operations to cool air for air conditioning and uses waste heat energy and solar energy to reactivate spent adsorbent.
Survey of prior art systems indicates, that the current air cooling systems using the adsorption dehumidification treatment step are not capable of producing the required low temperatures of air without the vapour compression or the absorption refrigeration treatments.